ga4_create_rollup_property_source_link

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden. It correctly flags the tool as a write operation and specifies required environment variables and confirmation. However, it does not disclose potential error conditions (e.g., if the source property is already linked) or whether the operation is idempotent, so transparency is adequate but not thorough.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise: one sentence plus a requirement line. It front-loads the category '[GA4 WRITE]' and includes only essential information. Every word contributes to understanding, with no redundancy or extraneous details.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has four parameters (including a nested body) and no output schema. The description covers the core purpose and key prerequisites but omits details about the 'body' parameter, error handling, or return behavior. While the schema fills some gaps, the description alone leaves an agent with incomplete operational context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% (all four parameters have descriptions). The description adds no additional meaning beyond the schema; it only mentions 'confirm' being required, which is already in the schema. Thus, the description provides no extra semantic value, earning a baseline score of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Add a source property to a rollup property'), identifies it as a GA4 WRITE operation, and specifies the scope (GA4 360). It distinguishes from the sibling 'ga4_delete_rollup_property_source_link' by mentioning 'no update', making the tool's purpose unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit prerequisites ('Requires GA4_MCP_ENABLE_WRITES=true and confirm=true') and notes that the tool does not support updates, guiding the agent when to use it. It lacks explicit alternatives for modification, but since no update tool exists, this is acceptable.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.